This study considers uncertainty about the number of surviving children. Under prohibition of child labor, a higher survival probability of a child can increase opportunities for education investment as the fertility rate declines with a temporary increase in the number of surviving children. However, per capita GDP may decrease until the start of education investment. When people accumulate their human capital, the effect of an increase in the survival probability would be ambiguous. By applying panel estimation, we examine economic development with the effect of child mortality on the fertility rate and number of surviving children.